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Biomedical subjects

S A Jovanovic

Publications and source records attributed to S A Jovanovic.

At least 19 recordsLinked to original sources
PubMed2001

Long-term evaluation of osseointegrated implants inserted at the time or after vertical ridge augmentation. A retrospective study on 123 implants with 1-5 year follow-up.

The purpose of the present study was to evaluate retrospectively, after 1 to 5 years of prosthetic loading, 123 implants consecutively inserted at the time of vertical ridge augmentation in 4 clinics. At the time of the implant surgery, 3 different techniques were used: the implants were allowed to protrude 2 to 7 mm from the bone level and a titanium reinforced expanded-polytetrafluoroethylene (e-PTFE) membrane was positioned to protect either the blood clot (Group A, 6 patients), or an allograft (Group B, 11 patients), or an autograft (Group C, 32 patients). The annual implant evaluation was carried out according to a standard protocol utilized for long term studies with endosseous implants inserted in non-regenerated bone. Only 1 implant failed immediately after the second stage surgery and after 1 month it was substituted with a new implant. All the remaining implants appeared clinically stable, no signs of radiolucency were present at the bone-implant interface, therefore, they could be defined successfully osseointegrated. The radiographic analysis showed stable bone crest levels with a mean bone loss of 1.35 mm for the Group A, of 1.87 mm for the Group B and of 1.71 for the Group C during the period of observation. Only 2 implants demonstrated an increased crestal bone loss of 3.5 mm and 4 mm respectively at the first year examination. On the base of these results, we can confirm previous long term studies on regenerated bone and we can conclude that vertically augmented bone with GBR techniques responds to implant placement like native, non-regenerated bone.

Adult↗
PubMed2001

Hyaluronan supports recombinant human bone morphogenetic protein-2 induced bone reconstruction of advanced alveolar ridge defects in dogs. A pilot study.

BACKGROUND: Prosthetic-driven implant dentistry requires predictable procedures for alveolar ridge augmentation. The objective of this pilot study was to evaluate bone regeneration in mandibular, full-thickness, alveolar ridge, saddle-type defects following surgical implantation of recombinant human bone morphogenetic protein-2 (rhBMP-2) in a novel hyaluronan (HY) sponge carrier. This sponge was fabricated from auto-crosslinked HY. METHODS: Alveolar ridge defects (approximately 15 x 10 x 10 mm), 2 per jaw quadrant, were surgically prepared in each of 3 young adult American fox hounds. Four defects were immediately implanted with rhBMP-2/HY. Three defects were implanted with rhBMP-2 in an absorbable collagen sponge (ACS) carrier (positive control). The rhBMP-2 solution (1.5 ml at 0.2 mg/ml) was soak-loaded onto the HY and ACS sponges. Three defects were implanted with HY sponges soak-loaded with buffer without rhBMP-2 (negative control), while 2 defects served as surgical controls. The animals were euthanized at 12 weeks postsurgery for histometric analysis. RESULTS: Clinically, alveolar ridge defects receiving rhBMP-2/ACS exhibited a slight supracrestal expansion, while defects receiving rhBMP-2/HY were filled to contour. In contrast, the HY and surgical controls exhibited ridge collapse. rhBMP-2/HY-treated defects exhibited a dense bone quality without radiolucent regions observed in defects treated with rhBMP-2/ACS. The histometric analysis showed 100% bone fill for the rhBMP-2/ACS defects and 94%, 58%, and 65% bone fill for the rhBMP-2/HY, HY, and surgical control defects, respectively. CONCLUSIONS: The conclusions are based on data from 2 of 3 animals in the study. In one animal, no response to rhBMP-2 was observed with either carrier, and the animal may have been a non-responder of unknown nature. With this limitation, the observations herein suggest that: 1) HY supports significant bone induction by rhBMP-2; 2) the rhBMP-2-induced bone assumes qualities of the immediate resident bone; 3) HY alone exhibits no apparent osteoconductive potential; and 4) HY appears to resorb within a 12-week healing interval in the absence or presence of rhBMP-2. Thus, HY appears to be a suitable candidate carrier for rhBMP-2.

Absorbable Implants↗
PubMed1999

Peri-implant tissue response to pathological insults.

With the increased use of osseointegrated implants and with many implants functioning for long periods of time, the soft tissue barrier around implants has become more important. This paper reviews the soft tissue response around implants under healthy and diseased conditions and presents the etiology of peri-implant tissue breakdown. Diagnostic techniques such as probing pocket depth, radiographic evidence, and microbial sampling have been analyzed and modified from the periodontal field and used during the maintenance phase of the dental implant. The long-term goal of implant maintenance is to prevent or to arrest the progression of disease, and to achieve a maintainable implant site. Recent reports indicate that peri-implant tissues can be treated with either non-surgical or surgical techniques.

Dental Implantation, Endosseous↗
PubMed1999

Autogenous bone harvesting: a chin graft technique for particulate and monocortical bone blocks.

The use of the mandibular symphysis for harvesting intraoral autografts in implant reconstruction cases is based on the ample supply of donor material, the proximity to the recipient site, and the ease of access to the tissue. This article discusses the technique of successful bone harvesting from the mandibular symphysis. As with other harvesting techniques, morbidity can occur. This report demonstrates a low morbidity rate and presents guidelines to help accomplish this.

Bone Transplantation↗
PubMed1998

Vertical ridge augmentation around dental implants using a membrane technique and autogenous bone or allografts in humans.

This study investigated the effect on vertical bone regeneration of the addition of demineralized freeze-dried bone allograft or autogenous bone chips to a membrane technique. Twenty partially edentulous patients with vertical jawbone deficiencies were selected for this study. The patients were divided into two groups of 10 individuals. The 10 patients of Group A received 26 Brånemark implants in 10 surgical sites. The 10 patients of Group B received 32 implants in 12 surgical sites. Fifty-two out of 58 implants (22 in Group A and 30 in Group B) extended 1.5 to 7.5 mm superior to the bone crest. Titanium-reinforced expanded polytetrafluoroethylene membranes were used to cover the implants and, before complete membrane fixation, demineralized freeze-dried bone allograft particles were condensed under the membrane in Group A, and autogenous bone chips were used in Group B. At the reentry after 7 to 11 months the membranes were removed and a small biopsy was collected from 11 sites comprehending the miniscrews. The clinical measurements from Group A demonstrated a mean vertical bone gain of 3.1 mm (SD = 0.9 mm, range 1 to 5 mm) with a mean percentage of bone gain of 124% (SD = 46.6%). The measurements from Group B showed a mean vertical bone gain of 5.02 mm (SD = 2.3 mm, range 1 to 8.5 mm) with a mean percentage of bone gain of 95% (SD = 26.8%). Histomorphometric analysis of the present study clearly demonstrated a direct correlation between the density of the pre-existing bone and the density of the regenerated bone. The mean percentage of new bone-titanium contact was from 39.1% to 63.2%, depending on the quality of the pre-existing bone. Both the clinical and histologic results indicate a beneficial effect of the addition of demineralized freeze-dried bone allograft or autogenous bone particles to vertical ridge augmentation procedures in humans.

Adult↗
PubMed1997

Localized bone reconstruction as an adjunct to dental implant placement.

Advances in bone reconstructive techniques, including the potential of barrier membrane usage for osteogenesis, have increased the indications for implant placement. This review discusses the critical biologic and clinical criteria involved in achieving a predictable success with barrier membranes. Experimental and clinical findings have shown that the type of adjunctive grafting material used, healing time of the membrane site, type and size of bone defect, and membrane exposure all influence the end result. Small bony defects like implant fenestrations and intact extraction sites seem not to depend on the application of membranes to regenerate bone membranes. Large bone grafts used for ridge reconstruction purposes might benefit from membranes, because they reduce the inevitable resorption of bone grafts when used alone. New developments in material and tissue engineering have introduced the use of resorbable membranes, xenografts, and osteoinductive proteins, such as recombinant human bone morphogenic protein, that are likely to play a role in the treatment of localized ridge deficiencies.

Alveolar Bone Loss↗
PubMed1995

Bone formation utilizing titanium-reinforced barrier membranes.

Advances in bone reconstructive techniques have increased the indications for implant placement in sites previously thought to be unsuitable. This clinical study evaluated a new surgical technique for the treatment of a variety of localized bone defects in four patients utilizing a titanium-reinforced membrane. The membrane material was developed to maintain a large protected space between the membrane and the bone surface without the need for a supportive device. Healing was uneventful in all sites, and the membranes were retrieved after 6 to 12 months. No residual defects were noted, resulting in an average change of implant exposure of 8.2 +/- 2.3 mm for sites with buccal dehiscences and from 5 to 6 mm ridge enlargement in localized bone defects. The quality of the regenerated tissue under the titanium-reinforced membrane appeared as bone structure with a superficial fibrous layer. This fibrous layer was more pronounced in sites treated with a membrane alone but was more than compensated by the quantity of new bone under the soft tissue. The results demonstrated that the use of a reinforced membrane appears to be a viable alternative for the clinical treatment of non-space-maintaining implant/bone defects. Further clinical and experimental investigations are recommended.

Adult↗
PubMed1994

Diagnosis and treatment of peri-implant disease.

With the increased use of osseointegrated implants and with many implants functioning for long periods of time, various complications have been reported. This paper reviews progressive loss of peri-implant bone--one of the major concerns during the function period of implants. The recognition and treatment of peri-implant bone loss around functioning implants is a major challenge for the clinician. Diagnostic techniques, such as probing pocket depth, radiographic tools, and microbial sampling have been modified from the periodontal arena and used during the maintenance phase of the dental implant. The long-term goals in the treatment of peri-implant disease are to arrest the progression of the disease and to achieve a maintainable site for the patient's implant. Recent reports indicate that peri-implant bony defects can be treated with either nonsurgical or surgical techniques. Bone regeneration is possible in selected peri-implant bony defects when appropriate surgical techniques are used, implant surface preparation is achieved, and the cause is eradicated.

Alveolar Bone Loss↗
PubMed1993

The management of peri-implant breakdown around functioning osseointegrated dental implants.

Peri-implant tissue breakdown can be the result of microbial action as well as of biomechanical and occlusal overload. The long-term goal of the treatment of peri-implant breakdown is to arrest the progression of the disease and to achieve a maintainable site for the patient. Peri-implant bony defects around functioning implants can be treated with either non-surgical or surgical (resective or regenerative) techniques. Bone regeneration is possible in selected peri-implant bony defects of functioning implants if appropriate surgical techniques are utilized and the etiologic cause is eradicated.

Alveolar Bone Loss↗
PubMed1993

The regenerative potential of plaque-induced peri-implant bone defects treated by a submerged membrane technique: an experimental study.

The aim of the present study was to experimentally induce peri-implant bone defects around three different types of implants by plaque accumulation and to determine whether new bone formation can occur on previously contaminated dental implants. Dental implants were placed into the mandibles of beagle dogs. Gross plaque accumulation around the implants was undisturbed for 3 months, which resulted in circumferential peri-implant bone defects. Bony defects surrounding the hydroxyapatite implants were significantly greater than those around the titanium implants. Surgical treatment consisted of granulation tissue removal, preparation of the implant surface, and the placement of an e-PTFE membrane over each test implant. Before the flap was closed to cover the implants, perforations were made into the cancellous bone. Each control implant received identical treatment, but without placement of a membrane. Surgical exposure after an uneventful submerged healing period showed evidence of closure of the peri-implant bone defects. Corresponding histologic examination of 2-month sections demonstrated large amounts of rapidly formed lamellar bone beneath the membrane. Some areas of the previously contaminated implant surface showed evidence of "re-osseointegration." These preliminary results support the hypothesis that plaque-induced peri-implant bone defects can be successfully treated by a submerged membrane technique in the dog model.

Alveolar Bone Loss↗
PubMed1992

Bone regeneration around titanium dental implants in dehisced defect sites: a clinical study.

Insufficient bone volume can be a significant problem when placing dental implants. This clinical study was designed to evaluate bone regeneration potential at dehisced dental implant sites. Nineteen titanium dental implants with exposed threads were studied. To create a secluded space for bone formation, an expanded polytetrafluoroethylene (e-PTFE) membrane was placed over the exposed implant sites secured with an implant cover screw and completely covered with the flap. Three membranes perforated the overlying soft tissue during the healing time and were removed prematurely. The remaining membranes were removed after an uneventful healing period of 4.5 to 6 months. Fourteen of 19 dehisced implant sites were completely covered with newly formed bonelike tissue; 4 implants demonstrated partial bone fill at reentry and 1 implant showed partial fill with soft tissue. In five implant sites a reentry was performed between 6 and 9 weeks; nonmineralized fibrous tissue was found to fill the space under the membrane. At 16 of the 19 implant sites there were similar dehiscence-type defects that were evaluated as a group. These dehiscences varied from 2.0 to 9.0 mm. The percentage of bone fill at reentry ranged from 28.4% to 100% (mean 89.6%; SD 22.51; SE 5.63) and was highly significant (P < .0001). Six to 12 months after prosthesis connection, 12 of the 19 implants were available for radiographic interpretation and an average bone loss of 1.73 mm (SD = 0.43) was measured. This surgical application of an e-PTFE membrane suggested a viable clinical method for enhancing bone formation around dental implants.

Adult↗
PubMed1990

Dental implant abutment resembling the two-phase tooth mobility.

Natural teeth and dental implants have differing degrees of mobility thus causing a potential biomechanical problem when connected by fixed bridgework. The clinical follow-up often discloses marginal bone loss around an implant neck probably due to high stress factors. An implant with a built-in compliance resembling the tooth mobility could be advantageous for stress distribution. With axial loading the proposed 'elastic'-test model accomplishes this demand. By means of theoretical and experimental studies this 'elastic'-test model is optimized and compared with a stiff implant-model. The results show a 20 times reduction of stress accumulation in bone with the 'elastic'-test model.

Biocompatible Materials↗
PubMedDate not supplied

Anterior implant-supported reconstructions: a surgical challenge.

Reconstructive procedures are able to provide improved aesthetics for implant patients who present with anatomical limitations (e.g., vertical or horizontal tissue loss) in the anterior maxilla. Aesthetic results, however, are directly related to the ability of the treatment team to reconstruct the lost bone and soft tissue, place the implant into its proper tridimensional position in the patient's arch, and use precise restorative techniques. This article presents comprehensive treatment steps for the utilization of single-unit and multiple-unit implant-supported restorations in the anterior maxilla.

Alveolar Ridge Augmentation↗
PubMedDate not supplied

Anterior implant-supported reconstructions: a prosthetic challenge.

Recent investigations have demonstrated that the successful utilization of anterior implant-supported restorations in the maxilla is dependent upon the satisfaction of numerous surgical and prosthodontic criteria. Conservative treatment alternatives that use a provisionalization phase can provide clinical benefits for patients with partial edentulism by guiding tissue maturation following completion of a meticulous surgical procedure. This article demonstrates a series of prosthetic considerations that guide contemporary aesthetic restorations, and highlights the underlying surgical factors related to this treatment.

Adult↗